The present invention relates to wireless networks, and in particular, to the problem of classifying interference sources using incomplete or minimal information.
Wireless digital networks are becoming ubiquitous in enterprises, providing secure and cost-effective access to resources. In operation, a plurality of access points (APs) advertise and provide wireless services to wireless clients. Client devices may range from the traditional such as laptop and other portable computers, to dual-mode phones, wireless data entry devices and scanners, wireless data acquisition systems, and more.
These wireless networks operate using frequencies and power levels assigned by regulatory agencies; the set of frequencies and power levels varies from regulatory domain to regulatory domain. The most common bands for wireless networks include frequency ranges around 2.4 GHz and 5 GHz.
In most regulatory domains, wireless networking systems are not the sole, or even primary users of a frequency band such as the 2.4 GHz band. As an example, in the United States, wireless networking devices operating to IEEE 802.11 standards are secondary users of the 2.4 GHz ISM band, operating under Part 15 of the FCC rules. As Part 15 devices, they must tolerate any interference from other authorized devices on the band. Those other devices on the band include microwave ovens, Bluetooth devices, a myriad of cordless phones, video and audio devices, and more. Additionally, Amateur Radio operators are authorized to use a portion of the 2.4 GHz band, covering channels 1 through 6, at power levels up to a kilowatt.
Wireless networks must live with, and adapt to such conditions. Detecting and dealing with interference from another wireless network is a fairly simple process; scan the available channels listening for other networks, and pick the channel which offers the best performance given the other users of the band.
For interference sources which are not other network devices, however, the process is not as simple. The first step is to classify non-network interference sources. Is the source intermittent or continuous? What frequency or frequencies does it cover? At what power levels? Are the effects localized to one or a small number of access points?
An additional challenge is to make these determinations using the wireless receivers present in devices such as network access points, laptops and other computing devices.